Ocean noise caused by shipping can cause humpback whales to dive more slowly and forage less frequently, according to new research in the journal Biology Letters.
A team of U.S. and U.K. researchers tagged 10 humpbacks in Stellwagen Bank National Marine Sanctuary, off the coast of Massachusetts, with devices that simultaneously tracked the whales’ movements and underwater noise. They found that as ship noise increased, the whales dove 15 percent more slowly and did one-third fewer side-roll feedings, a foraging technique humpbacks use to catch fish near the seafloor. The findings are the latest addition to a growing list of negative impacts from ocean noise on marine mammals, including disrupted communication, higher stress levels, and increased vulnerability as acoustic pollution masks predator movement. “Chronic impacts of even small reductions in foraging efficiency could affect individual fitness and translate to population-level effects on humpback whales,” the scientists wrote.
A humpback whale diving.